/*
 * HTTP Cookie:存储会话信息
 * 名称和值传送时必须是经过RUL编码的
 * cookie绑定在指定的域名下，非本域无法共享cookie，但是可以是在主站共享cookie给子站
 * cookie有一些限制：比如IE6 & IE6- 限定在20个；IE7 50个；Opear 30个...所以一般会根据【必须】需求才设定cookie
 * cookie的名称不分大小写；同时建议将cookie URL编码；路径是区分cookie在不同情况下传递的好方式；带安全标志cookie
 *     在SSL情况下发送到服务器端，http则不会。建议针对cookie设置expires、domain、 path；每个cookie小于4KB
 * */
//对cookie的封装，采取getter、setter方式
(function(global){
    //获取cookie对象，以对象表示
    function getCookiesObj(){
        var cookies = {};
        if(document.cookie){
            var objs = document.cookie.split('; ');
            for(var i in objs){
                var index = objs[i].indexOf('='),
                    name = objs[i].substr(0, index),
                    value = objs[i].substr(index + 1, objs[i].length);    
                cookies[name] = value;
            }
        }
        return cookies;
    }
    //设置cookie
    function set(name, value, opts){
        //opts maxAge, path, domain, secure
        if(name && value){
            // var cookie = encodeURIComponent(name) + '=' + encodeURIComponent(value);
            var cookie = name + '=' + value;
            //可选参数
            if(opts){
                if(opts.maxAge){
                    cookie += '; max-age=' + opts.maxAge; 
                }
                if(opts.path){
                    cookie += '; path=' + opts.path;
                }
                if(opts.domain){
                    cookie += '; domain=' + opts.domain;
                }
                if(opts.secure){
                    cookie += '; secure';
                }
            }
            document.cookie = cookie;
            return cookie;
        }else{
            return '';
        }
    }
    //获取cookie
    function get(name){
        return getCookiesObj()[name] || null;
    }

    //清除某个cookie
    function remove(name){
        if(getCookiesObj()[name]){
            document.cookie = name + '=; max-age=0';
        }
    }

    //清除所有cookie
    function clear(){
        var cookies = getCookiesObj();
        for(var key in cookies){
            document.cookie = key + '=; max-age=0';
        }
    }
    //获取所有cookies
    function getCookies(name){
        return getCookiesObj();
    }
    //解决冲突
    function noConflict(name){
        if(name && typeof name === 'string'){
            if(name && window['cookie']){
                window[name] = window['cookie'];
                delete window['cookie'];
                return window[name];
            }
        }else{
            return window['cookie'];
            delete window['cookie'];
        }
    }
    global['cookie'] = {
        'getCookies': getCookies,
        'set': set,
        'get': get,
        'remove': remove,
        'clear': clear,
        'noConflict': noConflict
    };
})(window);